1. Field of the Invention
This invention relates to a hand-held firearm that is provided with a detachable sight and specifically relates to the means by which said detachable sight is mounted on the receiver of the firearm. Said mounting means comprise a track, e.g., a rail track, which is provided on the top surface of the receiver of the firearm and adapted to slidably receive said detachable sight, at least one bore, which opens in the top surface of the housing at the bottom of the track, and a screw, which is mounted on said detachable sight and extends into said bore.
2. Description of the Prior Art
Numerous hand-held firearm are provided with detachable sights so that the firearm can be provided with a sight which has been selected in consideration of the actual shooting conditions and it is possible to use any of various rear sights which are available or a telescopic sight, a night sight and the like. The sights are provided at the bottom with a shoe, which is inserted into a rail track provided on the top surface of the receiver of the firearm and are fixed by means of a fixing screw. In the previous practice the fixing screw is usually mounted in a bore of the receiver and must be screwed into a mating tapped hole in the base of the sight. Because the sight must be forced in a centered position against the fixing screw during the rotation of the latter and owing to the upstanding screw cannot be inserted to a centered position in the rail track, the fixation of the detachable sight or the replacement of the detachable sight is a time-consuming and complicated operation.
Other known detachable sights are fixed by means of screws which are inserted from above through the body of the sight and screwed into tapped bores of the receiver of the firearm (U.S. Pat. No. 4,208,821). But the fixation of such detachable sights is also difficult and can be performed only with screwing implements and owing to a confined space often requires the detachable sight to be taken apart for the access to the fixing screws. It has also been proposed (Published German application No. 23 38 191) to secure a sight to a firearm by means of a fixing ring and a fixing member provided on the firearm. The fixing member receives a nut, and the sight proper is fixed by means of a fixing screw which is screwed into said nut. In that case the means for mounting the sight comprise a plurality of detachable parts and do not ensure an exact alignment of the sight relative to the firearm and for this reason such mounting means cannot be used to fix detachable sights.
It is known to provide a firearm not only with means for mounting a detachable sight but also with any of various means for adjusting such detachable sights. Such adjusting means comprise adjusting screws and adjusting nuts, which cooperate to adjust the detachable sight in vertical and/or lateral directions. In such arrangements the adjusting screw may additionally be used to hold the means for mounting the detachable sight in position (see U.S. Pat. Nos. 936,807 and 4,200,989 and Austrian patent specification No.196,756). But such adjusting means cannot be used as the only means for a rigid fixation of a detachable sight on the firearm so as to prevent any dislocation of the sight.